U.S. patent number 5,932,344 [Application Number 08/718,384] was granted by the patent office on 1999-08-03 for cement retarder and cement retardative sheet.
This patent grant is currently assigned to Daicel-Huels Ltd.. Invention is credited to Yoshiyuki Ikemoto, Toru Ikuta.
United States Patent |
5,932,344 |
Ikemoto , et al. |
August 3, 1999 |
Cement retarder and cement retardative sheet
Abstract
A cement retarder which comprises a saturated or unsaturated
polyester obtained by a reaction of a polycarboxylic acid component
comprising a polycarboxylic acid having 2 to 6 carbon atoms in the
main chain or its derivative, and a polyol component containing a
polyhydric alcohol having 2 to 4 carbon atoms or its condensate,
wherein: (a) the saturated polyester has a weight average molecular
weight of about 300 to about 50,000; or (b) the unsaturated
polyester has a weight average molecular weight of about 500 to
about 25,000; or (c) the polyhydric alcohol used to obtain the
saturated or unsaturated polyester is a condensate of a C.sub.2-4
alkylene glycol; or (d) the saturated polyester is a polyester
obtained by the use of a condensate of a C.sub.2-4 alkylene glycol
and has a weight average molecular weight of about 300 to about
50,000; or (e) the unsaturated polyester is a polyester obtained by
the use of a condensate of a C.sub.2-4 alkylene glycol and has a
weight average molecular weight of about 500 to about 25,000.
Inventors: |
Ikemoto; Yoshiyuki (Yokohama,
JP), Ikuta; Toru (Kobe, JP) |
Assignee: |
Daicel-Huels Ltd. (Tokyo,
JP)
|
Family
ID: |
26382042 |
Appl.
No.: |
08/718,384 |
Filed: |
October 7, 1996 |
PCT
Filed: |
February 07, 1996 |
PCT No.: |
PCT/JP96/00252 |
371
Date: |
October 07, 1996 |
102(e)
Date: |
October 07, 1996 |
PCT
Pub. No.: |
WO96/24563 |
PCT
Pub. Date: |
August 15, 1996 |
Foreign Application Priority Data
|
|
|
|
|
Feb 7, 1995 [JP] |
|
|
7-42373 |
Oct 30, 1995 [JP] |
|
|
7-305132 |
|
Current U.S.
Class: |
428/343; 525/444;
428/480; 528/308.6; 528/304; 528/302; 525/448; 428/482; 428/703;
525/445; 525/447; 525/437; 523/515; 523/500; 528/308.7; 525/452;
528/303; 528/306 |
Current CPC
Class: |
C04B
41/5323 (20130101); B44C 5/0438 (20130101); B44C
1/22 (20130101); C04B 24/283 (20130101); B44C
1/105 (20130101); C04B 24/26 (20130101); C04B
41/009 (20130101); C04B 24/283 (20130101); C04B
2103/20 (20130101); C04B 24/26 (20130101); C04B
2103/20 (20130101); C04B 41/5323 (20130101); C04B
28/02 (20130101); C04B 41/4513 (20130101); C04B
41/5323 (20130101); C04B 41/4511 (20130101); C04B
41/009 (20130101); C04B 28/02 (20130101); Y10T
428/2852 (20150115); Y10T 428/28 (20150115); Y10T
428/31786 (20150401); C04B 2103/22 (20130101); Y10T
428/31794 (20150401); C04B 2103/20 (20130101) |
Current International
Class: |
C04B
41/53 (20060101); C04B 24/28 (20060101); C04B
24/00 (20060101); C04B 24/26 (20060101); B44C
1/22 (20060101); B44C 1/00 (20060101); B44C
5/00 (20060101); B44C 5/04 (20060101); B44C
1/10 (20060101); B32B 013/12 (); B32B 027/06 ();
B32B 027/26 (); B32B 027/36 () |
Field of
Search: |
;428/703,141,143,195,206,207,210,44,47,48,49,51,482,480,343
;528/280,302,303,304,306,308,308.6,308.7
;525/5,437,445,446,447,448,452 ;523/500,515 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
0223592 |
|
May 1987 |
|
EP |
|
0401051 |
|
Dec 1990 |
|
EP |
|
2273677 |
|
Jan 1976 |
|
FR |
|
1057069 |
|
Oct 1983 |
|
JP |
|
61202803 |
|
Aug 1986 |
|
JP |
|
63-216703 |
|
Sep 1988 |
|
JP |
|
1172250 |
|
Jul 1989 |
|
JP |
|
58166006 |
|
Dec 1989 |
|
JP |
|
1775003 |
|
Jul 1991 |
|
JP |
|
3224953 |
|
Oct 1991 |
|
JP |
|
4-062107 |
|
Feb 1992 |
|
JP |
|
538711 |
|
Feb 1993 |
|
JP |
|
550411 |
|
Mar 1993 |
|
JP |
|
Primary Examiner: Chen; Vivian
Attorney, Agent or Firm: Birch, Stewart Kolasch & Birch,
LLP
Parent Case Text
This application is a 371 of PCT/JP96/00252, filed Feb. 7, 1996.
Claims
We claim:
1. A cement retarder which comprises a saturated polyester obtained
by a reaction of a polycarboxylic acid component comprising a
polycarboxylic acid having 2 to 6 carbon atoms in the main chain or
its derivative, and a polyol component containing a polyhydric
alcohol having 2 to 4 carbon atoms or its condensate, wherein
(a) said polyester has a weight average molecular weight of about
300 to about 50,000, or
(b) said polyester is obtained by use of said polyhydric alcohol
which comprises a condensate of a C.sub.2-4 alkylene glycol, or
(c) said polyester is obtained by use of said polyhydric alcohol
which comprises a condensate of a C.sub.2-4 alkylene glycol and has
a weight average molecular weight of about 300 to about 50,000.
2. A cement retarder as claimed in claim 1, wherein said
polycarboxylic acid is a saturated dicarboxylic acid having 2 to 5
carbon atoms in the main chain.
3. A cement retardative sheet which comprises a base sheet and a
composition held or supported by the base sheet, which composition
comprises a cement retarder as claimed in claim 1.
4. A cement retarder which comprises an unsaturated polyester
obtained by a reaction of a polycarboxylic acid component
comprising a polycarboxylic acid having 2 to 6 carbon atoms in the
main chain or its derivative, and a polyol component containing a
polyhydric alcohol having 2 to 4 carbon atoms or its condensate,
wherein
(a) said polyester has a weight average molecular weight of about
500 to about 25,000, or
(b) said polyester is obtained by use of said polyhydric alcohol
comprising a condensate of a C.sub.2-4 alkylene glycol, and has a
weight average molecular weight of about 500 to about 25,000.
5. A cement retarder as claimed in claim 4, wherein said retarder
comprises an unsaturated polyester obtained by a reaction of a
dicarboxylic acid component comprising an unsaturated aliphatic
dicarboxylic acid having 2 to 6 carbon atoms or its derivative in
the main chain, and a diol component comprising a diol having 2 to
4 carbon atoms or its condensate, and said polyester having a
repeating unit containing 4 to 9 carbon atoms as a main repeating
unit.
6. A cement retarder as claimed in claim 5, wherein said polyester
is a polyester obtained by a reaction of a dicarboxylic acid
component comprising an unsaturated aliphatic dicarboxylic acid
having 2 to 6 carbon atoms in the main chain or its derivative, and
at least one aromatic dicarboxylic acid selected from the group
consisting of phthalic acid, terephthalic acid and isophthalic acid
and their derivatives, and a diol component comprising a diol
having 2 to 4 carbon atoms or its condensate.
7. A cement retarder which comprises an unsaturated polyester which
is obtained by a reaction of a polycarboxylic acid component
comprising a polycarboxylic acid having 2 to 6 carbon atoms in the
main chain or its derivative, and a polyol component containing a
condensate of a C.sub.2-4 alkylene glycol.
8. A cement retarder as claimed in claim 1, or 4, wherein the main
repeating unit of the polyester comprises a repeating unit having 4
to 9 carbon atoms.
9. A cement retarder as claimed in claim 1, 4 or 7, wherein said
polycarboxylic acid component further contains an aromatic
dicarboxylic acid or its derivative.
10. A cement retarder as claimed in claim 9, wherein the content of
the aromatic dicarboxylic acid is 0.1 to 30% by weight based on the
total weight of the polyester.
11. A cement retarder as claimed in claim 9, wherein said aromatic
dicarboxylic acid is at least one species selected from the group
consisting of phthalic acid, terephthalic acid, isophthalic acid
and derivatives of these acids.
12. A cement retarder as claimed in claim 1, 4 or 7, wherein said
polyhydric alcohol is at least one species selected from the group
consisting of ethylene glycol, propylene glycol, trimethylene
glycol, tetramethylene glycol, dioxyethylene glycol, trioxyethylene
glycol, polyoxyethylene glycol, dioxypropylene glycol,
trioxypropylene glycol, polyoxypropylene glycol and glycerin.
13. A decorative material kit sheet which is produced by applying
plural decorative material continuously or as scattered on a
retardative layer having a cement retarder of claim 1, 4 or 7 and
tacky adhesive property or adhesive property.
14. A method for producing a dress finished concrete product, which
method comprises the steps of arranging the decorative material kit
sheet of claim 13 in a form, depositing an inorganic hardenable
composition into the form and hardening the composition, removing
the resultant hardened composition from the form, eliminating the
sheet having tacky adhesive property or adhesive property, and
washing the surface of the resultant hardened composition to
produce a decorated material.
15. A cement retarder as claimed in claim 1, 4 or 7, wherein said
polyester is in the form of a particle.
16. A cement retardative sheet which is composed of the polyester
of claim 1, 4 or 7.
17. A cement retarder as claimed in claim 4 or 7, wherein said
polycarboxylic acid is an unsaturated dicarboxylic acid having an
ethylenically unsaturated bond and containing 4 to 6 carbon atoms
in the main chain.
18. A cement retarder as claimed in claim 4 or 7, wherein said
polycarboxylic acid comprises maleic acid or maleic anhydride.
19. A cement retarder as claimed in claim 4 or 7, wherein said
polycarboxylic acid component comprises maleic acid or maleic
anhydride, and an aromatic dicarboxylic acid or its derivative.
20. A cement retarder as claimed in claim 4 or 7, wherein the
polyester has a weight average molecular weight of 500 to
5,000.
21. A cement retarder as claimed in claim 4, wherein said
unsaturated polyester is a reaction product of a dicarboxylic acid
component comprising at least maleic acid or its derivative, and a
diol component comprising an aliphatic diol having 2 to 4 carbon
atoms or its condensate.
22. A cement retarder as claimed in claim 4 or 7, wherein said
retarder comprises a cured product of the unsaturated
polyester.
23. A cement retarder as claimed in claim 22, wherein said cured
product is a cured product of a polymerizable composition
comprising the unsaturated polyester and a polymerization
initiator.
24. A cement retarder as claimed in claim 22, wherein said cured
product is a cured product of a polymerizable composition
comprising the unsaturated polyester, a polymerizable vinyl monomer
and a polymerization initiator.
25. A cement retarder as claimed in claim 24, wherein said
polymerizable vinyl monomer is a polymerizable monomer selected
from the group consisting of styrenic monomers, acrylic monomers
and methacrylic monomers.
26. A cement retarder as claimed in claim 24, wherein said
polymerizable composition comprises 1 to 500 parts by weight of the
polymerizable monomer relative to 100 parts by weight of the
unsaturated polyester.
27. A cement retarder as claimed in claim 22, wherein said cured
product is a cured product of a polymerizable composition
comprising at least one polymerization accelerator selected from
the group consisting of a cobalt salt of an organic acid, a
.beta.-diketone, an aromatic tertiary amine and a mercapto.
28. A cement retarder as claimed in claim 27, wherein the
concentration of the polymerization accelerator in the
polymerizable composition is 10 to 1,000 ppm.
29. A cement retarder as claimed in claim 22, wherein said cured
product is a particle.
30. A cement retardative sheet which comprises a base sheet and a
composition held or supported by the base sheet, which composition
comprises a cement retarder as claimed in claim 4 or 7.
31. A cement retardative sheet as claimed in claim 30, wherein said
sheet is obtained by applying or impregnating a composition
comprising the unsaturated polyester to a non-porous sheet or a
porous sheet, and heating the applied or impregnated sheet to cure
the composition.
32. A cement retardative sheet as claimed in claim 31, wherein said
unsaturated polyester-containing composition comprises the
unsaturated polyester and a polymerization initiator.
33. A cement retardative sheet as claimed in claim 31, wherein said
unsaturated polyester-containing composition comprises the
unsaturated polyester, a polymerizable monomer and a polymerization
initiator.
34. A cement retardative sheet as claimed in claim 30 or 3, wherein
said sheet is obtained by (1) applying or impregnating a
composition comprising a particulate polyester and a tacky adhesive
or an adhesive to a base sheet, or (2) adhering a particulate
polyester to a tacky adhesive layer or an adhesive layer of a base
sheet.
Description
TECHNICAL FIELD
This invention relates to a cement retarder (cement
hardening-retarder) which is useful for retardation of hardening of
the surface of a hardenable or curable composition comprising
cement, a cement retardative sheet as produced using the retarder,
and their use.
BACKGROUND TECHNOLOGY
A cement retarder is categorized into a cement admixture (a cement
additive) which is admixed with cement for the purpose of
retardation of setting and hardening of mortar or concrete by means
of retarding hydration of cement. With respect to a cement
retarder, Japanese Patent Application Laid-open No. 172250/1989
(JP-A-1-172250) mentions lead oxide, boron oxide, borax, zinc
chloride, zinc oxide, magnesium silicofluoride and other inorganic
retarders, polyhydroxy compounds (sugar, an alcohol, methyl
cellulose, ethyl cellulose, poly(vinyl alcohol), dextrin, etc.),
poly(sodium acrylate), a hydroxycarboxylate, a lignosulfonate,
gluconic acid or its salt, pyruvic acid, .alpha.-ketoglutaric acid
or other keto acids, and other organic retarders. The purpose of
the use of these cement retarders is to transport a ready-mixed
concrete over a long period with suppressing hardening of the
concrete in summer, and to mitigate a stress due to a temperature
(heat) in a large-sized concrete structure.
The surfaces of molded articles and various buildings made from
concrete are practically decorated with the use of aggregate
exposed finish by washing (washing finish) technology which is
categorized into plastering technologies. The washing finish
technology is a technology for exposing a part of aggregate by
washing immediately before hardening of the concrete and hence
washing out mortar of the surface layer of the concrete. According
to this technology, the washing should be conducted in an extremely
limited period (timing) since opportunity for washing closely
relates to the hardening rate (cure rate) of the concrete.
Therefore, the technology is unsuitable for commercial production
or large-sized building applications.
With respect to execution of tile works to a surface of concrete, a
technology using a unit tile as produced by disposing and adhering
plural of tiles on a surface of a tacky adhesive layer of a tacky
adhesive tape has been proposed. According to this technology using
the unit tile, tiles are applied by disposing the unit tile in a
form or shuttering to which concrete is placed or deposited,
pouring mortar into the form and curing the same, removing the
hardened product from the form and taking off the adhesive sheet to
expose the tiles on the surface of the concrete, and thereafter
removing the cement reached and cured on the surfaces of the tiles
to conduct surface finish. In the surface finish, the cured cement
adhered to the tiles may practically be scraped by hand and this is
an essential step for tile application (tile work) which is
characterized in a beautiful and tiny surface. The work for
removing the hardened cement adhered to tiles, however, takes much
time and trouble and is complicated so that the cost for tile
application increases and the removing treatment for hardened
cement would cause damage or defect of surfaces of the tiles.
For the purpose of solving these problems, technologies have been
proposed, which technologies comprise processing a surface of a
concrete product or forming a pattern on the surface by inhibition
of hardening of only the surface layer but no other part of the
concrete with the application of a cement retarder which is
categorized into cement additives. By way of illustration, a
process has been proposed, which process comprises impregnating a
retarder (hardening retarder) in paper, fixing the impregnated
paper on the bottom of a form by means of applying or posting,
depositing mortar into the form, and after hardening of the
concrete, removing the concrete molded article from the form, and
washing fresh mortar on the surface of the concrete which is in
contact with the impregnated paper to expose aggregate and hence to
obtain a natural feeling. Japanese Patent Application Laid-open No.
216703/1988 (JP-A-63-216703) discloses a process for forming a
predetermined convex-concave pattern (three-dimensional pattern) on
a surface of a concrete product, which process comprises a step of
cutting a pattern paper as produced by impregnating a retarder into
a paper to produce a cutting pattern paper corresponding to a
predetermined letter or figure or other pattern, a step of applying
the cutting pattern paper to a predetermined part of the inner
surface of a form, a step of depositing mortar into the form and
curing the mortar, a step of breaking up the form to take the
resultant concrete product off and a step of washing a part of the
concrete product corresponding to the pattern paper. Japanese
Patent Application Laid-open No. 202803/1986 (JP-A-61-202803)
discloses a process which comprises applying tiles or others to a
paper coated with the above-mentioned cement retarder, setting or
placing the tile-applied paper into a form and washing out the
product in the same manner as above.
Japanese Patent Application Laid-open Nos. 38711/1993
(JP-A-5-38711) and 50411/1993 (JP-A-5-50411) disclose a process
which comprises applying a mixture containing an ultra-retarder, a
tackifier, an extender or filler and a white pigment to an inner
surface of a form, depositing mortar or concrete into the form,
hardening the mortar or concrete and taking off the cured product
from the form, washing cement paste from the surface of the cement
product which is in contact with the form to finish the surface of
the cement product.
However, a conventional retarder which inhibits hydration mechanism
of cement has high solubility with respect to water, and hence is
dissolved in water or moisture in a cement concrete. Therefore, the
retarder dissolves accompanied with placement of mortar or
concrete, and flows in the form or the surface of a molded article
or structure together with an excessive bleed water in the mortar
or concrete. Accordingly, the retarder may flow into a portion
where washing finish is not required or it may concentrate locally,
and, to the contrary, the retarder may flow out from a portion
where washing finish or decorating is required. Further, the depth
of washing is particularly increased in a surface where bleeding
water has passed through. Therefore, a decorative letter or figure,
in particular a complicated decoration or ornament, can hardly be
formed with high accuracy in a predetermined part of a surface of a
concrete molded article or concrete building.
Japanese Patent Application Laid-open No. 224953/1991
(JP-A-3-224953) discloses a process for manufacturing a concrete
block integrated with an ornament material (decorative material),
which process comprises applying a concrete-hardening inhibitor
(concrete non-hardener) to an inner surface of a form (shuttering),
disposing an ornament such as a tile or stone through a joint rod,
composing a reinforcing steel (reinforcement) up to a predetermined
height, depositing concrete and hardening the concrete, removing
the hardened concrete from the form, and washing the surface of the
resultant concrete product with water. This literature discloses
that the concrete non-harder is incorporated into a composition
comprising an alkali swelling agent, a highly-water-absorbable
polymer, a water-absorbable monomer and a curing agent to cure the
composition, and thereby a highly-water-absorbable
polymer-containing cured film is obtained.
Japanese Patent Application Laid-open No. 175003/1991
(JP-A-3-175003) discloses a process for manufacturing a concrete
product decorated in a surface thereof, which process comprises
temporally adhering a decorative member, through an non-cured
coating layer, to an inner surface of a form (mold), depositing or
placing concrete to harden the concrete, and thereafter removing
the hardened product from the form, and taking off the non-cured
coating composition on the surface and uncured portion of concrete
of the resultant concrete product by washing with water. This
literature mentions that the non-cured coating layer is produced
with the use of a mixture of a polyester, poly(vinyl alcohol),
poly(vinyl acetal) or other alkali swelling agents, and a
highly-water-absorbable polymer.
According to the technologies described in these literatures, the
place of ornament disposed in the form is sifted or the concrete
non-curing agent flows out so that washing finished surface or
pattern can hardly be formed in a predetermined portion of a
concrete product. Further, since it is necessary to apply the
non-curing coating composition to the surface of an ornament,
improved workability and productivity of the concrete product would
not be expected. Incidentally, Japanese Patent Application
Laid-open No. 175003/1991 (JP-A-3-175003) mentions that the
concrete non-curing agent may be in the sheet form. However, the
concrete non-curing agent is composed of a mixture of the alkali
swelling agent and highly-water-absorbable polymer so that the
agent can hardly be molded into a sheet. Furthermore, a
highly-water-absorbable polymer is required in addition to the
alkali swelling agent in order to retard hardening (curing) of
cement, and there is no detail disclosure concerning the polyester
described as an example of the alkali swelling agent.
It is, therefore, an object of the present invention to provide a
cement retarder having a high inhibiting property with respect to
hardening of cement, despite its poor solubility in water.
It is another object of the invention to provide a cement retarder
which is useful for inhibiting flow out of the retarder due to
moisture, and forming a pattern or washing finished surface with
high accuracy on the surface of a concrete product.
A further object of the invention is to provide a retardative sheet
which insures inhibition of fluidization of a retarder when a
mortar composition is placed, and provides uniform inhibition of
hardening of the mortar in the contact surface with the mortar
composition and hence insures accurate formation of a pattern or
washing finished surface on a surface of a concrete product.
It is a yet another object of the invention to provide a sheet
which is useful for decorating a surface of concrete with an
ornament or others while inhibiting damage of the surface and hence
for providing a dress finished concrete product.
A still further object of the invention is to provide a retardative
sheet which insures easy and efficient formation of a pattern or
washing-finished surface on a surface of a concrete product.
It is an another object of the invention to provide a retardative
sheet which insures easy formation of a complicated pattern on a
surface of a concrete product and hence provides improved
decorating quality.
DISCLOSURE OF THE INVENTION
The inventors of the present invention made much investigation to
accomplish the above objects, and, as a result, found (1) that the
use of a polyester as produced by esterifying a specific
polycarboxylic acid component and a polyhydric alcohol component
for the formation of a high molecular weight compound results in
maintenance of insolubility with respect to water, and although the
polyester itself does not have inherent retarding property with
respect to cement, when mortar or concrete is deposited, the
polyester is gradually and effectively hydrolyzed by strong
alkalinity of the mortar or concrete, and hence a hydrolyzed
product (hydrolysate) exhibits remarkably effective retardancy with
respect to the cement accompanying with hardening of cement. They
further found (2) that supporting or holding of a retarder
(retardant) having retardancy (inhibiting activity) for hardening
of cement to a sheet results in accurate formation of a pattern or
washing finished surface on a surface of a concrete product. The
present invention has been accomplished based on the above
findings.
Thus, the cement retarder (cement hardening-retardant) comprises a
polyester obtainable by a reaction of a polycarboxylic acid
component comprising a polycarboxylic acid having 2 to 6 carbon
atoms in the main chain or its derivative, and a polyol component
comprising a polyhydric alcohol having 2 to 4 carbon atoms or its
condensate. The polycarboxylic acid may be a saturated dicarboxylic
acid having 2 to 5 carbon atoms in the main chain, or an
unsaturated dicarboxylic acid having 4 to 6 carbon atoms in the
main chain (backbone chain) and having an ethylenically unsaturated
bond, such as maleic acid and maleic anhydride. The polycarboxylic
acid component may further contain an aromatic dicarboxylic acid
such as phthalic acid or its derivative. The main repeating unit of
the polyester may comprise a repeating unit having 4 to 9 carbon
atoms.
The cement retarder may also comprise a cured product of an
unsaturated polyester, such as a cured product of (i) a
polymerizable composition comprising an unsaturated polyester and a
polymerization initiator, and (ii) a polymerizable composition
comprising an unsaturated polyester, a polymerizable vinyl monomer
and a polymerization initiator. The cured product may be used in
the form of powder or granule (particle).
The cement retardative sheet of the present invention includes (A1)
a cement retardative sheet comprising a base sheet and a
composition supported or held by the base sheet, which composition
comprises a cement retardant composed of a polyester obtainable by
a reaction of a polycarboxylic acid component comprising a
polycarboxylic acid having 2 to 6 carbon atoms in the main chain or
its derivative, and a polyol component comprising a polyhydric acid
having 2 to 4 carbon atoms or its condensate, and (A2) a cement
retardative sheet comprising a base sheet and a retardative layer
containing a concrete retarder and a tacky adhesive or an adhesive
formed on the surface of the base sheet, typically speaking.
The use of a sheet having tacky adhesive property or adhesive
property provides adhesion of a dressing material such as stone or
tiles to the retardative layer utilizing the tacky adhesive
property or adhesive property, and insures formation of a
homogeneous washing-finished surface or pattern on a surface of a
concrete and hence provides a concrete product with an excellent
decorative quality.
Therefore, when the retardative sheet (A2) is used, a decorative
material kit sheet is obtained by applying plural decorative
materials continuously or in scattered form to a retardative layer
having tacky adhesive property (pressure-sensitive adhesive
property) or adhesive property. Thus, a dressing-finished concrete
product is obtainable by disposing the above decorative material
kit sheet in a form (shuttering), placing an inorganic curable
composition and curing the composition, dislodging the cured or
hardened product from the form, removing the tacky adhesive or
adhesive sheet, and washing the surface of the exposed decorative
material.
Incidentally, the term "sheet" as used in the present specification
means a two-dimensional structure inclusive of a film, being
irrespective of its thickness. The term "derivative of a
polycarboxylic acid" as used herein includes an acid anhydride, and
a lower alkyl ester (e.g. C.sub.1-4 alkyl ester which is capable of
eliminating, such as a methyl ester and an ethyl ester) of a
polycarboxylic acid. The term "tacky adhesive or adhesive" may
generically referred to as "the tacky adhesive", and the terms
"tacky adhesive layer or adhesive layer" and "tacky adhesive
property or adhesive property" may generically be referred to as
"the pressure-sensitive adhesive layer" and "the pressure-sensitive
adhesive property", respectively. Further, the term "cement" means
an inorganic substance having curing or hardening property as mixed
with water, and includes an air-hardening cement (non-hydraulic
cement), a hydraulic cement and other cement, otherwise
specifically mentioned. The hardenable (curable) composition
comprising cement includes a cement paste, a mortar composition and
a concrete composition, and they may be simply and generically
referred to as "the inorganic hardenable composition".
BEST MODE FOR PRACTICING THE INVENTION
Cement retarder of the present invention
The cement retarder (cement hardening-retardant) of the present
invention comprises a polyester obtainable by a reaction of a
polycarboxylic acid component comprising a polycarboxylic acid or
its derivative, and a polyol (polyhydric alcohol) component
comprising a polyhydric alcohol or its condensate. The
polycarboxylic acid includes a saturated polycarboxylic acid shown
by the formula HOOCR.sup.1 COOH, wherein R.sup.1 represents a
direct bond of the both carboxyl groups, or an alkylene group
having 1 to 4 carbon atoms in the main chain, and an unsaturated
polycarboxylic acid having an ethylenically unsaturated bond or
other polymerizablly unsaturated bond, which is shown by the
formula HOOCR.sup.2 COOH, wherein R.sup.2 represents an aliphatic
hydrocarbon group having 2 to 4 carbon atoms in the main chain
(principle chain) and containing an unsaturated double bond. In the
above formulae, the alkylene group of R.sup.1 and the unsaturated
hydrocarbon group of R.sup.2 may be branched, but the number of the
carbon atom(s) of the substituent, such as an alkyl group, branched
from the main chain is not included in the number of the carbon
atom(s) of the main chains of R.sup.1 and R.sup.2. Hereinafter,
"the number of carbon atoms of the polycarboxylic acid" means the
number of carbon atoms in the main chain, otherwise particularly
specified.
As the polycarboxylic acid, wherein R.sup.1 is a direct bond or an
alkylene group having 1 to 4 carbon atoms in the main chain (that
is, the number of the carbon atom(s) of the main chain is 2 to 6
inclusive of the carbon atom of the carboxyl group), there may be
mentioned, for example, oxalic acid, malonic acid, succinic acid,
glutaric acid, adipic acid and others. The unsaturated
polycarboxylic acid wherein R.sup.2 is an unsaturated aliphatic
hydrocarbon group having 2 to 4 carbon atoms in the main chain
(namely an unsaturated hydrocarbon group having 4 to 6 carbon atoms
in the main chain inclusive of the carbon atoms of the carboxyl
group) includes aliphatic dicarboxylic acids (e.g. maleic acid,
maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride,
citraconic acid, citraconic anhydride, mesaconic acid, etc.). The
saturated carboxylic acid and the unsaturated carboxylic acid may
be used in combination with each other. These polycarboxylic acids
may be employed singly or in combination.
The polycarboxylic acid component may further comprise, in addition
to the above polycarboxylic acid, an aliphatic polycarboxylic acid
(e.g. azelaic acid, sebacic acid, etc.) or an aromatic
polycarboxylic acid (e.g. phthalic acid, phthalic anhydride,
terephthalic acid, isophthalic acid, trimellitic acid, pyromellitic
acid, etc.). In particular, the use of a polycarboxylic acid
component containing an aromatic dicarboxylic acid or its
derivative selected from the group consisting of phthalic acid,
terephthalic acid, isophthalic acid and derivatives of these acids
is useful for adjusting or controlling the characteristics of the
saturated or unsaturated polyester, such as strength, elongation,
flexibility, plasticity, water-resistance or others.
The content of the aromatic polycarboxylic acid based on the total
of the polyester is, for instance, about 0.1 to 30% by weight,
preferably about 0.1 to 20% by weight (e.g. about 1 to 15% by
weight), and more preferably about 0.1 to 10% by weight (e.g. about
2 to 10% by weight).
The preferred polycarboxylic acid includes (1) a dicarboxylic acid
component comprising a saturated or unsaturated aliphatic
dicarboxylic acid having 2 to 6 carbon atoms or its derivative
(particularly, a dicarboxylic acid component comprising a saturated
aliphatic dicarboxylic acid having 2 to 5 carbon atoms, or at least
maleic acid or its derivative), or (2) a dicarboxylic acid
component comprising a saturated or unsaturated aliphatic
dicarboxylic acid having 2 to 6 carbon atoms or its derivative, and
at least one aromatic dicarboxylic acid selected from the group
consisting of phthalic acid, terephthalic acid and isophthalic
acid, or a derivative of these acids. Typically preferred
polycarboxylic acid component comprises (3) a saturated
dicarboxylic acid having about 2 to 4 carbon atoms or its
derivative, (4) an unsaturated dicarboxylic acid having 4 or 5
carbon atoms or its derivative (in particular, maleic acid or
maleic anhydride), or (5) a combination of the above saturated
dicarboxylic acid (3) and/or the unsaturated dicarboxylic acid (4)
(particularly, maleic acid or maleic anhydride), and an aromatic
dicarboxylic acid or its derivative (in especial, an aromatic
C.sub.8 dicarboxylic acid or its derivative).
As examples of the polyol component, there may be mentioned
polyhydric alcohols each having 2 to 4 carbon atoms, such as diols
(e.g. ethylene glycol, propylene glycol, trimethylene glycol,
1,3-butanediol, tetramethylene glycol and other C.sub.2-4 alkylene
glycols), polyoxyalkylene glycols as condensates of a C.sub.2-4
alkylene glycol, such as dioxyethylene glycol, trioxyethylene
glycol, polyoxyethylene glycol (hereinafter these substances may
simply and generically be referred to as "the polyethylene glycol",
otherwise specified), dioxypropylene glycol, trioxypropylene
glycol, polyoxypropylene glycol (hereinafter these may be simply be
referred to as "the polypropylene glycol" otherwise particularly
referred to), polyoxytetramethylene glycol and so on; polyols (e.g.
glycerin, diglycerin, polyglycerin). These polyol components may be
used independently or in combination.
The preferred polyhydric alcohol includes, ethylene glycol,
propylene glycol, trimethylene glycol, tetramethylene glycol,
dioxyethylene glycol, trioxyethylene glycol, polyoxyethylene
glycol, dioxypropylene glycol, trioxypropylene glycol,
polyoxypropylene glycol, and glycerin. The polyhydric alcohol may
practically comprise a diol component, in particular, a diol
component composed of an aliphatic diol having 2 to 4 carbon atoms
or its condensate.
The molecular weight of the polyoxyalkylene glycol may be such that
the weight average molecular weight is about 100 to 7,500, and
preferably about 200 to 5,000 (e.g. about 200 to 2,500). When the
polyethylene glycol is used, it may practically have a weight
average molecular weight of not greater than 300.
The glycol component comprising propylene glycol or the
polypropylene glycol is useful for imparting flexibility and
hydrophilic property and for enhancing solubility with respect to a
polymerizable monomer such as a styrenic or acrylic monomer.
The polyhydric alcohol may be employed, as necessary, in
combination with other polyol such as trimethylolethane,
trimethylolpropane and pentaerythritol.
The main repeating unit --(R.sup.a COOR.sup.b OCO)--, wherein
R.sup.a represents a residue of a polycarboxylic acid, and R.sup.b
represents a residue of a polyhydric alcohol, of the polyester may
practically be composed of a repeating unit having 4 to 9 carbon
atoms (that is, a repeating unit in which the total number of the
carbon atoms of the polycarboxylic acid and the polyhydric alcohol
is 4 to 9).
Among these polyesters, an unsaturated polyester, in particular an
unsaturated polyester containing maleic acid or maleic anhydride as
the polycarboxylic acid component, can preferably be employed.
The molecular weight of the polyester is not particularly limited
and may be selected from the range where the weight average
molecular weight is, for example, about 300 to 100,000 (e.g. about
300 to 25,000), preferably about 300 to 50,000 (e.g. about 500 to
15,000) and more preferably about 500 to 20,000. The molecular
weight of the unsaturated polyester is such that the weight average
molecular weight is about 300 to 100,000, preferably about 300 to
50,000 and more preferably about 500 to 10,000. The unsaturated
polyester may practically have a weight average molecular weight of
about 300 to 5,000 (e.g. about 500 to 5,000) and particularly about
500 to 2,500. The molecular weight means a weight average molecular
weight, in terms of styrene, determined by gel permeation
chromatography.
The polyester may be either in an oily or solid form. The oily
polyester as intact, and the solid polyester as dissolved in an
organic solvent, may be applied or impregnated to a base sheet
(e.g. a non-porous sheet such as a plastic sheet and a metal foil,
a porous sheet such as paper and a nonwoven fabric), or applied to
the inner bottom or internal side wall of a form made from wood,
for instance, with the use of a brush or spray. The solid polyester
may be employed in the form of a particle (powder or granule), or
may be heated and molten to apply or impregnate to the base
sheet.
The polyester inclusive of the unsaturated polyester can be
obtained by a conventional technology, such as a process which
comprises condensing the polycarboxylic acid component and the
polyhydric alcohol component in the presence of a catalyst. When an
unsaturated polycarboxylic acid such as maleic acid or maleic
anhydride is used, the condensation reaction may practically be
conducted in the presence of hydroquinone or other radical
polymerization inhibitor. The ratio of the polyhydric alcohol can
be selected from the range of about 0.5 to 3 equivalents and
preferably about 0.7 to 2 equivalents relative to 1 equivalent of
the polycarboxylic acid. A polyester having a low molecular weight
may practically be obtained by using one component between the
polycarboxylic acid component and the polyol in an excess
amount.
The cement retarder of the present invention may be composed of the
polyester, or when the polyester is an unsaturated polyester, it
may be composed of a cured product of the unsaturated
polyester.
The cured product of the unsaturated polyester can be obtained by
curing the polymerizable composition (i) comprising the unsaturated
polyester and a polymerization initiator. As the polymerization
initiator, use can be made of any of various organic peroxides,
such as methyl ethyl ketone peroxide, cumene hydroperoxide, benzoyl
peroxide, t-butyl peroxybenzoate, t-butylperoxy-2-ethylhexanoate,
dicumyl peroxide and so forth. The amount of the polymerization
initiator may be selected from the range not interfering with
polymerizability, and is for instance about 0.5 to 5 parts by
weight, preferably about 1 to 4 parts by weight and practically
about 2 to 3 parts by weight relative to 100 parts by weight of the
unsaturated polyester.
Such polymerizable composition (i) insures an improved handling
property by using as a powdery cement retarder as produced by
self-crosslinking the unsaturated polyester with the polymerization
initiator, even when the unsaturated polyester constituting the
cement retarder has a low molecular weight such as an oily
polyester which is poor in handling property. The polymerizable
composition (i) containing an unsaturated polyester having a weight
average molecular weight of about 300 to 5,000 has a comparatively
low viscosity and hence has a high applicability or impregnating
property with respect to the base sheet. The polymerizable
composition can be held or supported by the sheet as a crosslinked
composition by means of curing.
The cured product of the unsaturated polyester may be a cured
product of the polymerizable composition (ii) comprising the
unsaturated polyester, a polymerizable vinyl monomer (a reactive
diluent) and the polymerization initiator. The polymerizable vinyl
monomer includes, for example, styrene, .alpha.-methylstyrene,
vinyltoluene and other styrenic monomers, methyl (meth)acrylate,
ethyl (meth)acrylate, butyl (meth)acrylate and other alkyl
(meth)acrylates each having about 1 to 20 carbon atoms in the alkyl
group, particularly about 1 to 10 carbon atoms, 2-hydroxyethyl
(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl
(meth)acrylate, (meth)acrylic acid, glycidyl (meth)acrylate and
other monomers each having a functional group (e.g. hydroxyl group,
carboxyl group, glycidyl group and so on), esters of (meth)acrylic
acid and the above-mentioned polyhydric alcohol (e.g. the
polyethylene glycol) such as ethylene glycol di(meth)acrylate and
polyethylene glycol di(meth)acrylate. As the vinyl monomer, use may
also be made of vinyl acetate and other vinyl esters, vinyl
chloride and other halogen-containing vinyl monomers, acrylonitrile
and other vinyl cyanide, ethylene, propylene and other olefinic
monomers. These polymerizable monomers may be employed singly or in
combination.
The preferred vinyl monomer includes styrenic monomers, acrylic
monomers and methacrylic monomers.
The proportion of the polymerizable vinyl monomer may be selected,
according to the molecular weight of the unsaturated polyester,
from a range not adversely affecting the retarding property or the
handling property of the unsaturated polyester, and is, for
instance, about 1 to 500 parts by weight (e.g. about 1 to 100 parts
by weight), preferably about 5 to 200 parts by weight (e.g. about 5
to 100 parts by weight) and practically about 5 to 30 parts by
weight relative to 100 parts by weight of the unsaturated
polyester.
The polymerizable composition (ii) is easy to take out from a
reactor even when it comprises a solid or viscous unsaturated
polyester because of addition of the polymerizable vinyl monomer,
and even when the unsaturated polyester is liquid or viscous which
is difficult to be handled, the composition has an improved
handling property by crosslinking and curing the unsaturated
polyester to use as a powdery cement retarder. Further, the
polymerizable composition (ii) can be supported or held as a
crosslinked composition by a base sheet by means of applying or
impregnating the composition to the base sheet and curing the
composition.
The cured product of the unsaturated polyester may be a cured
product of a polymerizable composition (iii) which comprises a
polymerization accelerator (polymerization promotor) in addition to
the constitutive components of the above-mentioned polymerizable
composition (i.e. the unsaturated polyester and the polymerization
initiator each constituting the polymerizable composition (i), or
the unsaturated polyester, the polymerizable vinyl monomer and the
polymerization initiator each constituting the polymerizable
composition (ii)). The polymerization accelerator includes, for
example, cobalt naphthenate, cobalt octylate and other organic acid
salts of cobalt, acetylacetone, ethyl acetoacetate and other
.beta.-diketones, aromatic tertiary amines, a mercapto and others.
These polymerization accelerators may be used independently or in
combination.
The concentration of the polymerization accelerator (polymerization
promoter) in the polymerizable composition may be selected within
the range of, for instance, about 10 to 1,000 ppm, preferably about
10 to 500 ppm (e.g. about 10 to 100 ppm), and the accelerator may
practically be used in a concentration of about 30 to 50 ppm.
The curing (crosslinking) of the unsaturated polyester can be
carried out at ambient temperature (room temperature), but it is
advantageous to conduct the curing at about 60 to 200.degree. C.
for curing the unsaturated polyester in a short period (e.g. about
0.5 to 50 minutes).
As described above, the cement retarder of the present invention
may be composed of an oily or solid (e.g. a particulate) saturated
polyester or unsaturated polyester. The cured product of the
unsaturated polyester as the retarder may be employed in the form
of a particle (powder or granule) or used as supported or held by
the base sheet as a crosslinked composition. The particle size of
the particulate saturated polyester or unsaturated polyester and
the particulate cured product is not strictly limited, and may
optionally be selected within the range of an average particle size
of about 0.1 to 1,000 .mu.m, and preferably about 0.1 to 500
.mu.m.
The cement retarder of the invention may be used in combination
with other retarder. Further, the cement retarder of the invention
may comprise, according to the species of the polyester, a variety
of additives, such as pigments, dyes and other coloring agents,
ultraviolet ray absorbers, antioxidants and other stabilizers,
polymerization inhibitors, plasticizers, antifoaming agents,
emulsifiers, hydrolysis accelerators, inorganic salts, metallic
oxides, sand and other fillers.
The polyester itself constituting the cement retarder of the
invention scarcely has retardative property with respect to cement,
or even if it has retardative property, the retardative property is
extremely small. Further, being different from conventional
retarders, the retarder of the invention is hardly dissolved in
water, and hence scarcely flows with a bleeding water from mortar
or concrete. However, the ester bond of the polyester is hydrolyzed
due to strong alkalinity of the uncured mortar or concrete, and
hence carboxyl group and hydroxyl group, which are useful for
retardation, are liberated. The rate of hydrolysis increases
accompanied with utilization of the water in the mortar or concrete
for hardening of the cement, and the rate becomes maximum due to
heat derived from the concrete during the curing, and further when
the curing is conducted under heating, due to the heat thereof, and
the liberated carboxyl group and hydroxyl group synergistically
exhibit great retardative activity. On the other hand, the concrete
at the stage, where the retardative activity is exhibited, is yet
uncured but already has no fluidity, and hence when the retardative
component is liberated due to hydrolysis of the polyester, the
retardative component does no more move as dissolved in bleeding
water. Therefore, the retardative activity (retardative property)
can be exhibited at desired part or portion and no other, and a
letter, a picture and other patters can be formed by washing-finish
after hardening of the cement.
Although the cement retarder of the invention is useful for the
formation of a desired pattern with high accuracy, it can also be
added to mortar or concrete for the same applications as
conventional retarders, such as long-term inhibition of hardening
of a ready-mixed concrete in summer, or mitigation of stress due to
heat (temperature) in a large-sized concrete structure.
Cement retardative sheet of the present invention
The cement retardative sheet of the invention can roughly be
classified into (A1) a retardative sheet which comprises a base
sheet and a composition comprising the cement retarder composed of
the saturated or unsaturated polyester supported or held by the
base sheet, or (A2) a retardative sheet which comprises a base
sheet and a retardative layer comprising the concrete retarder and
a tacky adhesive or an adhesive formed on the base sheet.
Cement retardative sheet (A1)
In the cement retardative sheet (A1), the composition comprising
the saturated or unsaturated polyester is held or supported by the
base sheet. The composition may be used as intact when the
polyester is in the oily form. The polyester may be heated and
molten to be applied or impregnated to the base sheet, and
irrespective of its shape (e.g. a solid), the polyester may be used
as dissolved in an organic solvent. As the organic solvent, there
may be mentioned, for example, ethanol, isopropanol and other
alcohols, hexane and other aliphatic hydrocarbons, cyclohexane and
other alicyclic hydrocarbons, benzene, toluene, xylene and other
aromatic hydrocarbons, dichloromethane, dichloroethane and other
halogenated hydrocarbons, acetone, methyl ethyl ketone and other
ketones, ethyl acetate and other esters, diethyl ether,
tetrahydrofuran and other ethers, and mixtures of these
solvents.
When the polyester is the unsaturated polyester, the polyester may
be used as either of the above-mentioned polymerizable
compositions, that is, (i) the polymerizable composition comprising
the unsaturated polyester and polymerization initiator, (ii) the
polymerizable composition comprising the unsaturated polyester,
polymerizable monomer and polymerization initiator, or (iii) the
polymerizable composition as prepared by adding the polymerization
accelerator to the compositions (i) or (ii).
Further, when the polyester is in the particulate form (in
especial, a particle of the cured product of the unsaturated
polyester), the polyester may be employed as a composition
comprising the particle of the polyester and a tacky adhesive or
adhesive. The tacky adhesive or the adhesive includes, for
instance, naturally-occurring rubbers, synthetic rubbers, (e.g.
neoprene, isoprene) and other rubber-series pressure-sensitive
adhesives, poly(vinyl acetate), an ethylene-vinyl acetate copolymer
and other vinyl acetate-based elastomers, acrylic rubber and other
acrylic elastomers, polyester elastomers and so on. These tacky
adhesives may be any of emulsion tacky adhesives or solution tacky
adhesives. Furthermore, water-soluble viscous substances can also
be used, and such substances include, for example, poly(vinyl
alcohol), poly(acrylic acid), polyacrylamide, methyl cellulose,
hydroxyethyl cellulose, carboxymethyl cellulose and other synthetic
water-soluble polymers, locust bean gum, guar gum, gum arabic,
tragacanth rubber, pectin, sodium alginate, carragheenin and other
naturally-occurring water-soluble polymers. These tacky adhesives
and adhesives may be employed singly or in combination. The tacky
adhesive composition may be use in combination with a tackifier
(e.g. petroleum resins, terpene resins, dicyclopentadiene-series
resins and other hydrocarbon resins, rosin derivatives). The
composition of the tacky adhesive or adhesive may comprise an
inorganic filler for controlling or regulating tackiness of the
composition.
In the composition comprising particles of the polyester and the
tacky adhesive or adhesive, the content of the tacky adhesive or
adhesive may only be within the range not deteriorating retardative
property, tackiness or adhesive property, and is, for example,
about 10 to 2,000 parts by weight, preferably about 50 to 1,000
parts by weight and more preferably about 100 to 500 parts by
weight relative to 100 parts by weight of the particulate
polyester.
The base sheet includes a plastic sheet, a metal foil and other
non-porous sheets, and paper, a woven or non-woven fabric and other
porous sheets, typically speaking. Among these base sheets, the
preferred non-porous sheet includes a plastic sheet, and the
desirable porous sheet includes a plastic non-woven fabric.
There is no particular restriction for the constitutive polymer of
the base sheet, and the polymer includes, for instance,
polyethylene, polypropylene and other olefinic polymers;
poly(ethylene terephthalate), poly(butylene terephthalate) and
other polyesters (especially, a poly(alkylene terephthalate)); an
ethylene-vinyl acetate copolymer, an ethylene-acrylic acid
copolymer; acrylic resins; polystyrene; poly(vinyl chloride);
polyamide; polycarbonate; poly(vinyl alcohol), an ethylene-vinyl
alcohol copolymer and the like. These polymers can be used singly
or in combination. The preferable base sheet includes a plastic
sheet or non-woven fabric as produced by using poly(ethylene
terephthalate) or other poly(alkylene terephthalate). The base
sheet may also be a sheet improved in hand-tearability or
dimensional stability.
The base sheet may be either of a single sheet or a composite sheet
as produced by laminating plural layers, such as a composite sheet
produced by laminating one side or both sides of a cloth made of
woven fibers such as polyethylene fibers, with the sheet such as
polyethylene. The base sheet such as a plastic sheet may be either
of a non-oriented sheet or monoaxially or biaxially oriented sheet.
Further, the surface of the base sheet may be subjected to surface
treatment such as flame treatment, corona discharge treatment and
plasma treatment in order to improve the adhesive property with
respect to the composition comprising the polyester. The surface
tension of the base sheet of which surface has been treated may
practically be not less than about 40 dyne/cm.
The thickness of the base sheet may be selected from the range not
adversely affecting workability and mechanical strength, and is,
for example, about 15 to 500 .mu.m, preferably about 20 to 400
.mu.m, more preferably about 30 to 300 .mu.m and practically about
50 to 300 .mu.m.
The shape or form of the supporting of the polyester (preferably
the unsaturated polyester) with respect to the base sheet is not
particularly restricted, and can be selected according to the
species of the composition comprising the polyester. By way of
illustration, the polyester may be supported or held by the base
film by means of applying or impregnating the base sheet with the
composition comprising the saturated or unsaturated polyester, or
applying or impregnating the base sheet with any of the
polymerizable compositions (i) to (iii) and heating the same to
cure or crosslink and thereby to form a crosslinked composition as
held or supported by the base sheet. The polymerization or
crosslinking of the polymerizable composition may be conducted at
an ambient temperature (room temperature) but, usually, at a
temperature not lower than 100.degree. C. (e.g. about 100 to
200.degree. C.), preferably about 100 to 170.degree. C. (e.g. about
100 to 150.degree. C.) and practically about 120 to 150.degree.
C.
The composition comprising the particulate polyester and the tacky
adhesive or adhesive may be held or supported by the base sheet by
means of applying or impregnating the composition to the base
sheet. Further, when the particulate (powdery or granular)
polyester is used, the polyester may be held or supported on the
base sheet by applying the particulate polyester to a tacky
adhesive layer (pressure-sensitive adhesive layer) or adhesive
layer formed on the surface of the base sheet by means of
scattering or spreading. Incidentally, the particulate polyester
may be obtained in a manner according to the form of the polyester,
for example, by cooling and pulverizing the polyester.
The thickness of the sticky adhesive layer containing the
particulate polyester is, for instance, about 30 to 500 .mu.m,
preferably about 100 to 500 .mu.m, more preferably about 150 to 300
.mu.m and practically about 200 to 250 .mu.m.
Cement retardative sheet (A2)
The cement retardative sheet (A2) comprises a base sheet, and a
retardative layer comprising a concrete retarder and a tacky
adhesive or an adhesive and formed on the base sheet. As the
concrete retarder, use can be made of other retarder in addition to
the above-mentioned polyester.
As the base sheet, tacky adhesive or adhesive, there may be used
the similar base sheet, tacky adhesive and adhesive to those
mentioned above.
The species of the other retarder than the polyester is not
particularly restricted as far as being a hardening retarder or
setting retarder which retards hardening rate of cement, and any of
inorganic or organic retarders can be employed. The inorganic
retarder includes a phosphoric acid, a boric acid or salts of these
acids, hexafluorosilicate and so forth.
As the organic retarder, there may be mentioned, for instance,
phosphonic acid compounds each having a phosphono group PO.sub.3
H.sub.2, and non-phosphonic acid-based compounds.
Phosphonic acid-series retarder
The phosphonic acid-series retarder includes
aminodi(methylenephosphonic acid), aminotri(methylenephosphonic
acid), 1-hydroxyethylidene-1,1-diphosphonic acid,
ethylenediaminetetra(methylenephosphonic acid),
diethylenetriaminepanta(methylenephosphonic acid),
hexamethylenediaminetetra(methylenephosphonic acid) or salts
thereof.
Examples of the salt include salts with ammonia, sodium, potassium
and other alkali metals, calcium, and magnesium, barium and other
alkaline earth metals. As the salt of the phosphonic acid-series
compound, there may be mentioned, for example, pentasodium
aminotri(methylenephosphonate), tetrasodium
1-hyroxyethylidene-1,1-diphosphonate, calcium sodium
ethylenediaminetetra(methylenephosphonate), potassium
hexamethylenediaminetetra(methylenephosphonate), sodium
diethylenetriaminepenta(methylenephosphonate) and so on.
Non-phosphonic acid-series retarder
As examples of the non-phosphonic acid retarder, there may be
mentioned glycolic acid, lactic acid, malic acid, tartaric acid,
citric acid, gluconic acid, and other hydroxycarboxylic acids or
their salts; oxalic acid, malonic acid and other saturated
polycarboxylic acids, fumaric acid, itaconic acid and other
unsaturated polycarboxylic acids, glucoheptanoic acid and other
polycarboxylic acids or their salts; poly(maleic acid),
poly(fumaric acid), a styrene-maleic acid copolymer, poly(acrylic
acid), poly(methacrylic acid), a styrene-(meth)acrylic acid
copolymer, a (meth)acrylate-(meth)acrylic acid copolymer, an
ethylenesulfonic acid-acrylic acid copolymer and other homo- or
co-polymer of a monomer having a carboxyl group or salts thereof
(preferably, a low molecular weight polymer or its salt);
antioxidants (e.g. ascorbic acid, isoascorbic acid, etc.); polymers
such as polyhydroxysilane and polyacrylamide (preferably, a polymer
with a low molecular weight); carbohydrates (e.g. sucrose and other
polysaccharides, corn syrup, etc.); fumic acid; lignin sulfonic
acid or a lignosulfonate (e.g. calcium lignosulfonate) and
others.
Among these retarders, use can advantageously be made of at least
one component selected from the group consisting of phosphonic acid
compounds, hydroxycarboxylic acids, polycarboxylic acids, homo- or
co-polymers of a monomer having a carboxyl group, isoascorbic acid,
phosphoric acid, boric acid or their salts, polyhydroxysilane and a
haxafluorosilicate. As the retarder, phosphonic compounds,
hydroxycarboxylic acids, polycarboxylic acids, isoascorbic acid or
salts of these acids may practically be used. In particular, a
combination of a phosphonic acid compound and a hydroxycarboxylic
acid can advantageously be employed. Such combination includes, for
instance, a combination of aminotri(methylenephosphonic acid) and
citric acid. The relative proportion of the phosphonic acid
compound to the hydroxycarboxylic acid is such that the former/the
later equals about 100/25 to 500 (by weight), and preferably about
100/50 to 250 (by weight). The preferred retarder may practically
contain an acidic group (e.g. phosphonic acid group, carboxyl
group, sulfonic acid group) or its salt, and may practically be
water-soluble. The retarders may be used independently or in
combination.
The amount of the concrete retarder is, relative to 100 parts by
weight of the tacky adhesive or adhesive, about 5 to 1,000 parts by
weight, preferably about 10 to 700 parts by weight, and more
preferably about 25 to 500 parts by weight. The concrete retarder
may practically be used in a proportion of about 25 to 400 parts by
weight (e.g. about 50 to 300 parts by weight) relative to 100 parts
by weight of the tacky adhesive or adhesive.
Where necessary, the composition comprising the retarder and tacky
adhesive or adhesive may further comprise an organic solvent or an
additive as mentioned above.
The cement retardative sheet (A2) can be obtained by applying a
composition comprising the retarder and tacky adhesive or adhesive
to the base sheet, and drying the resultant product.
In the retardative sheets (A1) and (A2), the composition comprising
the retarder may only be applied at least one side of the base
sheet.
The cement retardative sheet may also be (A3) a sheet composed of a
resin having cement retardative property (e.g. the polyester such
as the unsaturated polyester), or (A4) a sheet composed of a
composition comprising the cement retarder. Incidentally, the sheet
(A3) comprising the retardative resin may contain the retarder.
The retardative sheets (A3) and (A4) may be prepared with the use
of a composition containing a retardative resin, or the retarder
and a sheet-formable resin, by a conventional molding technology
such as extruding, fluid-extending, calendaring and others.
As examples of the sheet-formable resin, there may be mentioned
thermoplastic resins (e.g. polyethylene, polypropylene and other
olefinic polymers; poly(ethylene terephthalate), poly(butylene
terephthalate), poly(1,4-dimethylol-cyclohexane terephthalate) and
other polyesters; nylon 46, nylon 6, nylon 66, nylon 610, nylon
612, nylon 11, nylon 12 and other polyamides; poly(vinyl acetate),
an ethylene-vinyl acetate (EVA) copolymer, a vinyl acetate-vinyl
vasaticate copolymer (VA-VeoVa) and other vinyl ester-series
resins; poly(vinyl alcohol), an ethylene-vinyl alcohol copolymer
and other saponified products of vinyl ester-series resins; an
ethylene-ethyl acrylate copolymer, an ethylene-(meth)acrylic acid
copolymer; poly(vinyl chloride), a vinyl chloride-vinyl acetate
copolymer, a vinylidene chloride-vinyl acetate copolymer,
polychloroprene and other halogen-containing polymers; an acrylic
resin, a styrene-(meth)acrylate copolymer and other acrylic
polymers; polystyrene, a styrene-butadiene copolymer, a
styrene-butadiene-acrylonitrile copolymer and other styrenic
polymers; methyl cellulose, hydroxyethyl cellulose, cellulose
acetate and other cellulosic polymers; naturally-occurring
polymers, etc.), thermosetting resins (e.g. thermosetting acrylic
resins, unsaturated polyester resins, vinyl ester resins, diallyl
phthalate resins, epoxy resins, urea resins, phenol resins and so
on). These resins may be used singly or in combination. Typically
preferred resin as the sheet-formable resin is practically a
hydrophilized resin such as a hydrophilic resin (e.g. a
water-soluble or water-dispersible resin) or a latex or an
emulsion.
The proportion of the retarder in the retardative sheet (A4) is,
for example, about 5 to 1,000 parts by weight, preferably about 10
to 700 parts by weight, more preferably about 25 to 500 parts by
weight and practically about 25 to 400 parts by weight (e.g. about
50 to 300 parts by weight) relative to 100 parts by weight of the
resin.
The cement retardative sheet may also be (A5) a sheet which has
been imparted with tacky adhesive property or adhesive property by
means of incorporating a tacky adhesive or an adhesive into a
sheet, or application of the tacky adhesive or adhesive to the
sheet. The content of the tacky adhesive in the sheet (A5)
containing the tacky adhesive is, for instance, about 10 to 500
parts by weight, preferably about 25 to 400 parts by weight and
more preferably about 50 to 300 parts by weight relative to 100
parts by weight of the retardative resin or sheet-formable resin.
The sheet (A5) may practically contain the tacky adhesive in an
amount of 25 to 250 parts by weight relative to 100 parts by weight
of the retardative resin or sheet-formable resin.
When the tacky adhesive layer or adhesive layer is formed by
application or coating, the tacky adhesive layer or adhesive layer
may be formed, according to the species and content of the
retarder, in a thickness of about 0.1 to 150 .mu.m, preferably
about 1 to 120 .mu.m and more preferably about 10 to 100 .mu.m,
typically speaking.
Further, the retardative sheet may also be a retardative sheet (A6)
composed of a non-tacky adhesive or non-adhesive retardative layer
as produced in the same manner as the retardative layer of the
retardative sheet (A2) except for using a binder resin in leu of
the tacky adhesive or adhesive.
As the binder resin, there may be mentioned, for instance,
poly(vinyl acetate), poly(vinyl alcohol), an ethylene-vinyl acetate
copolymer, an ethylene-ethyl acrylate copolymer, an acrylic
polymer, polystyrene, a styrene-acrylate copolymer, a polyester, a
polyacetal, poly(vinyl chloride), a vinyl chloride-vinyl acetate
copolymer, a polyamide, a polyurethane, a polycarbonate, a
chlorinated polypropylene and other chlorinated polyolefins, acetyl
cellulose, acetylbutyl cellulose, ethyl cellulose, nitrocellulose
and other cellulosic polymers, elastomers (e.g. a
naturally-occurring rubber, a chlorinated rubber, a
hydrochlorinated rubber, butadiene rubber, isoprene rubber, a
styrene-butadiene rubber, an acrylonitrile-butadiene rubber, butyl
rubber, chloroprene rubber, an ethylene-propylene rubber, an
ethylene-propylene-nonconjugated diene rubber, an acrylic rubber, a
chlorosulfonated polyethylene rubber, silicone rubber, a urethane
rubber, etc.). These binder resins may be used singly or in
combination.
The proportion of the retarder is, for example, relative to 100
parts by weight of the binder resin, about 5 to 1,000 parts by
weight, preferably about 10 to 700 parts by weight, more preferably
about 25 to 500 parts by weight, and practically about 25 to 500
parts by weight (e.g. about 50 to 400 parts by weight).
Moreover, the retardative sheet may be a retardative sheet (A7) as
produced by forming a tacky adhesive layer or an adhesive layer on
the surface of any of the retardative sheets (A1) to (A6). When the
sheets (A1), (A2) or others have tacky adhesive property, the tacky
adhesive layer or adhesive layer is not always required. The tacky
adhesive layer or adhesive layer may only be formed at least on one
side of the sheet having retardative property. As the tacky
adhesive or adhesive, any of those as mentioned above can be
employed.
The thickness of the tacky adhesive layer may be selected from the
range in which the tacky adhesive property can be exhibited and
inhibiting activity with respect to hardening of concrete is not
adversely affected, and is, for example, about 0.1 to 50 .mu.m
(e.g. about 1 to 50 .mu.m), preferably about 1 to 40 .mu.m, more
preferably about 2 to 30 .mu.m and practically about 2 to 25
.mu.m.
Preferably, the tacky adhesive layer is a layer from which the
retarder is capable of leaching. The tacky adhesive layer from
which the retarder can leach may be formed homogeneously on the
surface of the retardative sheet, or heterogeneously thereon. When
the tacky adhesive layer is formed homogeneously, the thickness of
the layer is preferably thin, such as about 0.1 to 15 .mu.m,
preferably about 1 to 10 .mu.m and more preferably about 1 to 5
.mu.m. In case the tacky adhesive layer is formed heterogeneously,
a scattered tacky adhesive layer may be formed as a regular pattern
or an irregular pattern by means of a technology such as coating or
printing, irrespective of the thickness of the layer.
When the surface of the retardative sheet has tacky adhesive
property (tackiness), the tacky surface may practically be coated
with a releasable protective sheet or paper such as a releasing
paper (separating paper).
The retardative sheet may be cut suitably and used as a surface
decorative sheet. By way of an example, a decorative finished
(dressing finished) concrete product can be obtained by fixing, by
means of applying, for instance, the cut retardative sheet to a
part of an internal wall of a form corresponding to the washing
part of the resultant concrete product, placing concrete, allowing
the concrete to harden, thereafter removing the hardened concrete
from the form, and washing off unhardened mortar of the surface of
the concrete product corresponding to the part where the sheet has
been applied to. Further, since the polyester as the cement
retarder is supported or held by the base sheet, the retarder does
not move when the concrete is placed, and the retarder is scarcely
soluble in water so that it does not flow with bleeding water.
Accordingly, a decorative pattern such as a letter or figure can
clearly be formed with high accuracy on a desired surface portion
of a concrete molded article (shaped article) or building.
The coating layer or retardative layer each comprising the retarder
(hereinafter may briefly referred to as "the coating layer") in the
retardative sheet may be releasable from the base sheet. When the
coating layer is releasable from the base sheet, an optional
portion or area corresponding to a desired pattern or figure in the
coating layer is cut and released from the base sheet, the
resultant sheet is disposed in a form, an inorganic hardenable
composition (e.g. a mortar composition) is placed in the form to
give a cured and hardened concrete product, and the contact surface
of the concrete product in contact with the sheet is washed to give
a washing finished surface in which a design, figure pattern or
aggregate is exposed in a portion corresponding to the non-cut part
of the surface of the concrete product. For the purpose of forming
a releasable coating layer, the surface of the base film may be
untreated, or treated with a mold releasing agent (mold lubricant)
such as a wax, a higher fatty acid amide, a silicone oil and so on.
The surface tensile of the base sheet may be relatively selected,
in relation with the adhesive strength of the coating layer, from a
range not interfering with the releasing property of the coating
layer. The surface tensile of the coating layer is, for instance,
not greater than 38 dyne/cm, preferably about 20 to 38 dyne/cm, and
more preferably about 25 to 36 dyne/cm.
The retardative sheet being imparted with tacky adhesive property
by means of the tacky adhesive (pressure-sensitive adhesive agent)
is useful for production of a concrete product having a figure,
design or washing surface on the surface thereof, or a concrete
product which is integrated and fixed with a decorative material
(an ornamental material). That is, the sheet is laid in a mold or
form as the tacky adhesive surface being an upper side, the surface
sides of plural dressing materials such as stones or tiles are
arranged to the tacky adhesive surface by means of adhesion, and
the decorative materials are located and fixed. Thereafter, an
inorganic hardenable (curable) composition is deposited in the form
(mold), and cured or hardened by means of a conventional hardening
technology such as curing, and the hardened molded article is taken
out from the mold. Thus, by washing the surface side (the contact
side with the sheet) with water, a pressurized water or a jet
stream, uncured composition attached to the dressing material can
easily be removed, and, by removing the tacky adhesive, a concrete
product as laminated with the cleaned surface-dressing materials
(e.g. a dressed block, a precast concrete slab, etc.) can be
obtained. When the dressing materials are not adhered to the tacky
adhesive surface of the sheet, the aggregate is exposed by washing
and hence a pattern or washing surface can be formed.
The sheet laid in the form is in contact with the form on the face
and hence the contact area is great so that rupture or misplacing
due to placing of the inorganic hardenable composition can be
inhibited. Therefore, the sheet is not required to be temporally
fixed to the form by a temporally fixing means such as a
pressure-sensitive adhesive double coated tape, but where
necessary, the sheet may be temporarily fixed to the form with a
temporally fixing means. Further, a joint sealant or joint filler
(e.g. a joint rod made of a flexible plastic such as a
polyurethane) for inhibiting adhesion of a mortar composition or
others may be disposed in a gap portion (joint portion) between the
disposed dressing materials, or a gap portion (joint portion)
between the form and the dressing materials.
When the sheet composed of the coating layer or retardative layer
containing the tacky adhesive is used, a kit sheet as produced by
previously arranging or disposing a decorative material to the
tacky adhesive layer may be disposed in the form without direct
arrangement of the decorative material in the form. By way of
illustration, a unit tile can be formed by applying plural tiles as
decorative materials to the tacky coating layer continuously or as
scattered in the surface direction on the surface of the layer. The
plural tiles may practically be arranged adjacently each other
(continuously) or with intervals in the surface direction (e.g. in
a longitudinal direction, transverse direction (cross direction),
or both longitudinal and transverse directions). The use of the
decorative material kit sheet insures an improved working
efficiency, since respective or separate arrangement of the
decorative materials in the mold is not required and it is
sufficient to dispose the decorative material kit sheet prepared in
the other step in the mold.
The decorative material includes various materials such as boulders
or cobblestones, black stones, Teppei stones and other
naturally-occurring stones, artificial stones an other stones,
tiles and other ceramic materials, metallic materials, glass, wood,
woven fabrics and others. The decorative material may have a plane
form, and the tile may be a mosaic tile or a divided tile. Further,
where necessary in the production of the objected concrete product,
the inorganic hardenable composition may be placed after disposing
a reinforcement (reinforcing steel) or other reinforcing material
into the form (mold).
The decorative material kit film such as the unit tile is useful
for production of a dressing-finished concrete product inclusive of
a precast concrete slab. That is, the decorative kit sheet is
disposed as the back of the decorative material such as tiles being
upper side in a form for concrete placement, a concrete is disposed
in the form and cured, the hardened concrete is removed from the
form, and the tacky adhesive sheet is removed to expose the surface
of the decorative material. Thereafter, a precast concrete slab
integrated with the decorative material can be obtained by washing
the surface of the decorative material and hence washing out the
uncured inorganic hardenable composition (e.g. cement, etc.) which
has reached the surface of the decorative material. Namely, when
the inorganic hardenable composition reaches the surface of the
decorative material such as tiles, the retardant component in the
sheet or retardative layer inhibits hardening or curing of the
inorganic hardenable composition, and hence the inorganic
composition remains semi-hardened (semi-hardened or unhardened)
state. Therefore, surface finish for removing the inorganic
hardenable composition from the surface of the decorative material
can be conducted efficiently and completely by means of a simple
and easy manner of washing such as washing with water.
The cement includes, for instance, an air-hardening cement (e.g.
gypsum (plaster), slaked lime, dolomite plaster and other lime); a
hydraulic cement (e.g. Portland cement, high-early-strength
Portland cement, alumina cement, rapid-hardening high-strength
cement, calcined gypsum and other self hardening cement; lime slag
cement, blast-furnace-cement; cement mixtures). The preferable
cement includes gypsum, dolomite plaster and hydraulic cement,
typically speaking.
The cement may be used as a paste composition (cement paste) with
water, or a mortar composition or concrete composition containing
sand, quartz sand, pearlite or other fine aggregates and/or coarse
aggregates. When a pattern is formed with the use of the
retardative sheet by means of an aggregate which has been exposed
to the surface accompanied with washing, a mortar composition
containing an aggregate, among them a coarse aggregate, may be
practically used. The surface of at least a part of the coarse
aggregate may practically be smooth for the purpose of enhancing
decorative quality.
The paste composition and the mortar composition may contain, as
necessary, any of various additives such as coloring agents,
hardening agents, calcium chloride and other hardening accelerator,
sodium naphthalenesulfonate and other water reducing agents,
coagulants, carboxymethyl cellulose, methyl cellulose, poly(vinyl
alcohol) and other thickeners, foaming agents, synthetic resin
emulsions and other waterproof agents, and plasticizers.
INDUSTRIAL APPLICABILITY OF THE INVENTION
The cement retarder and retardative sheet of the present invention
are useful for production of various concrete products such as a
curtain wall, a wall and other concrete panels, and concrete
blocks, in particular for the manufacture of dressed concrete
products (e.g. precast concrete slabs) .
EXAMPLES
The following examples are intended to describe the present
invention in more detail but should by no means limit the scope of
the invention.
Example 1 and Comparative Example 1
A 1-liter three neck flask provided with a stirrer and a
thermometer was charged with 204 g of ethylene glycol and 296 g of
oxalic acid (mole ratio equals 1:1), and, with stirring, the
charged was heated from ambient temperature to 150.degree. C. with
taking 3 hours, and thereafter heated from 150.degree. C. up to
210.degree. C. with taking 24 hours. The moisture produced during
the above reaction was continuously removed from the reaction
system, and the reaction was ceased at the point when the
temperature reached 210.degree. C. to give an oily polyester.
Polyesters were obtained in the same manner as above except for
combinations of any of polyhydric alcohols and any of
polycarboxylic acids shown in Table 1 in lieu of the combination of
ethylene glycol and oxalic acid.
As a comparative example, a polyester was prepared in the similar
manner to the above except that pentanediol and phthalic acid were
used instead of ethylene glycol and oxalic acid, respectively.
The obtained polyesters were oily and the weight average molecular
weights thereof were within the range of 2,000 to 8,000.
The properties of the oily polyesters as retarders were evaluated
in the following manner. That is, a polypropylene container having
a caliber of 12 cm was charged with 600 g of a mortar containing
Portland cement/sand/water=100/200/55 (by weight), and the surface
of charged was smoothed. To the smoothed mortar was inserted and
buried partially a polypropylene ring (caliber 5 cm, height 3 cm,
thickness 0.3 mm) as the height being half. The oily polyester was
poured into the ring as the height of the layer being 2 to 3 mm
within 10 minutes after the preparation of the mortar and hence the
polyester was flowed and extended on the furnace of the mortar. The
top of the polypropylene container was sealed with a wrapping film
for food and the sealed container was allowed to stand for 1
hour.
Thereafter, the whole of the polypropylene container was
transferred into an oven at 50.degree. C. and was allowed to stand
for 8 hours for curing. After the curing, the polypropylene
container was taken out and allowed to stand for 55 hours at room
temperature for the hardening of the mortar. The ring and remained
oily polyester were removed from the hardened mortar, and the
contact face of the oily polyester and mortar was washed with a
tooth brush while washing with water. The washed product was
air-dried and the washing quality was evaluated by visual
observation according to the following criteria.
Further, a blank test was conducted where washing was carried out
in the same manner as above except that the oily polyester was not
used. In the blank test, the surface of the hardened mortar was
dense and smooth. Furthermore, particle shape of the sand was
scarcely observed, and the surface showed homogeneously a cement
color over the whole thereof.
Excellent: Remarkable retardative effect, concave formation in a
depth of 2 to 5 mm on the surface of the mortar,
Fair: Particles of the sand exposed, clear difference being
observed in roughness and color tone between the inner area and the
outer area of the ring,
Good: Difference of the color tone being apparently observed due to
exposure of the sand in comparison with the blank test or the outer
area of the ring, but there being little difference in the
smoothness of the surfaces, the extent of the exposure of the sand
particles being small,
Poor: No difference from the blank test observed in the external
appearance.
TABLE 1 ______________________________________ Oxalic Succinic
Maleic Fumaric Adipic Phthalic acid acid acid acid acid acid
______________________________________ EG Fair Fair Excellent Fair
Good Poor PG Good Good Excellent Good Good Poor BD Good Good Fair
Good Poor Poor Glycerin Good Good Fair Good Good Poor PD Poor Poor
Good Poor Poor Poor ______________________________________ In the
table, the symbols for the polyhydric alcohols mean as follows: EG
Ethylene glycol, PG: Propylene glycol, BD: 1,4butanediol, PD:
1,5pentanediol
Example 2
A 10-liter autoclave provided with a stirring blade was charged
with 3,452 g (35.2 moles) of maleic anhydride and 2,539 g (40.9
moles) of ethylene glycol, and to the charged were added 100 ppm of
hydroquinone as a polymerization inhibitor and 50 ppm of
tetra-n-butoxytitanium as a polymerization catalyst. The resultant
charged was stirred and heated from ambient temperature to
150.degree. C. with taking 3 hours, and heated from 150.degree. C.
up to 210.degree. C. with taking 24 hours, under atmospheric
pressure (ordinary pressure), while nitrogen gas being circulated
for removing moisture produced with the reaction, and thereafter
the reaction was ceased. The obtained unsaturated polyester was
cooled to 80.degree. C., and, to 100 parts by weight of the oily
unsaturated polyester (weight average molecular weight 2,250) were
added and mixed 3 parts by weight of an organic peroxide (Nippon
Oil and Fats Co., Ltd., "PERBUTYL-O") and 50 ppm of cobalt acetate
as a crosslinking catalyst. The resultant mixture was poured into a
stainless steel bat (25 cm.times.40 cm.times.5 cm) as the height
being 2 cm, and heated in a furnace at 120.degree. C. for 15
minutes to be cured.
The cured product was cooled to room temperature, roughly
pulverized with a crusher, and further pulverized into particles
having a mean particle size of 200 .mu.m or less by means of a
refrigerating grinder to give a powdery cement retarder.
This powdery cement retarder was scattered homogeneously over the
whole of a tacky adhesive-coated side of a 5 cm-width tape coated
with a tacky adhesive (Nichiban Co., Ltd., Strong Adhesive Type for
Corrugated Cardboard Packing), and excessive powder was removed
aside. The obtained tape was applied to the bottom of a wood form
for concrete slab (inner volume 1 m.times.1 m.times.(depth) 10 cm)
at intervals of 10 cm as the power-adhered side being upside.
In the form was placed a mortar composed of Portland
cement/sand/water=100/200/55 (by weight) as the height of the
placed mortar being 3 cm, and reinforcing steel bars (diameter 1
cm.times.80 cm) were arranged in the form at intervals of 20 cm,
and the mortar was further placed so as the total height of the
placed mortar being 6 cm. The resultant was allowed to stand at
ambient temperature (room temperature) for 168 hours, and the
hardened molded plate was removed from the form, the tacky adhesive
tape was eliminated, and the washing was conducted by washing by
means of a scrubbing brush while washing with water. As a result,
only the contact part in contact with the tape was washed out in a
depth of 2 to 3 cm, and washing surfaces of 5 cm in width having a
natural color of sand and a coarse surface due to the sand particle
were clearly formed at intervals of 10 cm.
Example 3
A polymerizable composition was prepared by adding and mixing 10
parts by weight of 2-hydroxyethyl methacrylate, 3 parts by weight
of an organic oxide (Nippon Oil and Fats Co., Ltd., "PERBUTYL-O")
and 50 ppm in concentration of cobalt acetate as a crosslinking
catalyst to 100 parts by weight of an oily unsaturated polyester as
prepared in the same manner as Example 2. The polymerizable
composition was applied to a 50-.mu.m thickness polyethylene
terephthalate sheet in a coating amount of 50 g/m.sup.2, and the
coated sheet was passed through an oven at 150.degree. C. for 30
seconds for heating to be cured, and thereby a cement retardative
sheet was obtained. This sheet was slitted to provide lengthy
sheets each having a width of 5 cm.
These lengthy sheets were applied, in a lattice form at intervals
of 10 cm, to an internal wall (inner wall of 1 m.times.1 m) of a
concrete form (30 cm.times.1 m.times.(depth) 1 m) as the coated
surface being in the face to the internal side of the form. To the
form was placed the same mortar as Example 2 and was hardened for
168 hours, and the hardened mortar was removed from the form.
By washing the surface of the hardened mortar in the same manner as
Example 2, the contact portion in contact with the cement
retardative sheet was washing-finished in a depth of about 2 mm to
form a distinct cross-cut (lattice) pattern.
Example 4
A viscous oily unsaturated polyester (weight average molecular
weight 1,950) was prepared in the same manner as Example 2, except
for using 3,603 g (31.1 moles) of maleic anhydride and 2,674 g
(29.1 moles) of glycerin. To 100 parts by weight of the unsaturated
polyester was added 10 parts by weight of butyl acrylate, and to
100 parts by weight of the total amount of the both components was
added 3 parts by weight of an organic peroxide (Nippon Oil and Fats
Co., Ltd., "PERBUTYL-O"), and these components were mixed at
50.degree. C. to prepare a solution of a polymerizable
composition.
This polymerizable composition was impregnated to a polyester
nonwoven fabric having a weight (Metsuke) of 30 g/m.sup.2, and
excess composition was removed by squeezing the nonwoven fabric
with a roll. The impregnated nonwoven fabric was heated in an oven
at 150.degree. C. for 30 seconds to give a cement retardative
sheet.
The retardative sheet was spread all over the bottom of the wood
form used in Example 2, square tiles (10 cm.times.10
cm.times.(thickness) 8 cm) and joint rods (square form with cross
section of 10 mm.times.10 mm) were arranged reciprocally on the
sheet and the mortar used in Example 2 was deposited thereto. The
mortar was allowed to stand at ambient temperature for 168 hours
for hardening, and the resultant concrete molded article was
removed from the form, and the surfaces of the tiles were washed
with water. As a result, attachment on the surfaces of the tiles
were smoothly removed only by means of washing with water, and
removing work with the use of a wire brush or a spatula was not
required.
Example 5
The process of Example 2 was repeated except for using 3,450 g
(35.2 moles) of maleic anhydride and 2,800 g (45.2 moles) of
ethylene glycol to give an oily unsaturated polyester (weight
average molecular weight 540). The unsaturated polyester was
applied with a brush at intervals of 10 cm and in a width of 10 cm
to the bottom of the wood form used in Example 2. The mortar as
employed in Example 2 was deposited in the form at a height of 5
cm, reinforcing steels used in Example 2 were arranged at intervals
of 20 cm in the form and the mortar was further deposited so as the
total height of the mortar to be 10 cm. The mortar was hardened in
the same manner as Example 2 and the hardened concrete molded
article was removed from the form and was washed out. Hence, only
in the applied portion of the oily unsaturated polyester, the sand
and cement were washed out in a depth of about 2 mm. In the washed
portion after drying was formed a scabrous surface with a shallow
grave, which scabrous surface had a natural color of sand, and had
sand particles exposed to the surface. The uncoated part to which
the unsaturated polyester had not been coated was hardened, and the
retardative effect of the unsaturated polyester did not reach
there.
Example 6
An oily saturated polyester (weight average molecular weight 490)
was prepared in the same manner as Example 5 except that 4,090 g
(34.6 moles) of succinic acid and 2,770 g (44.6 moles) of ethylene
glycol were employed. By using the obtained saturated polyester,
the cement retardative property was evaluated in the same manner as
Example 5, and as a result, only the part applied with the oily
saturated polyester was washed to form a comparatively smooth
washing-finished surface having a natural color of sand.
Example 7
A polymer was obtained by conducting a reaction in the same manner
as Example 5 except for employing 3,430 g (35.0 moles) of maleic
anhydride and 2,387 g (38.5 moles) of ethylene glycol, continuing
the reaction for further 13 hours after the reaction temperature
reached 210.degree. C., and ceasing the reaction at the point when
stirring became impossible. This polymer was glassy at room
temperature and insoluble in a solvent so that the molecular weight
of the polymer could not be determined by gel permeation
chromatography. The polymer was pulverized with a crusher and a
refrigerating pulverizer using a liquid nitrogen to give powder
having a mean particle size of not greater than 200 .mu.m.
The retardative property was evaluated in the same manner as
Example 2, except that the powder was scattered to a tape coated
with a tacky adhesive, and as a result, only the part in contact
with the tape was washed in a depth of about 2 mm to form distinct
washing-finished surfaces with a width of 5 cm at intervals of 10
cm.
Examples 8 to 10 and Comparative Example 2
Unsaturated polyesters were obtained in the same manner as Example
2, except for using the polycarboxylic acid components and
polyhydric alcohol components shown in Table 2. The weight average
molecular weights of the obtained unsaturated polyesters were also
shown in Table 2.
TABLE 2 ______________________________________ Comp. Ex. 8 Ex. 9
Ex. 10 Ex. 2 ______________________________________ Maleic
anhydride (g) 3312 3136 2460 1676 (mole) 33.8 32.0 25.1 17.1
Terephthalic acid (g) 232 531 1677 3005 (mole) 1.4 3.2 10.1 18.1
(%)* 5 10 30 50 Ethylene glycol (g) 2538 2538 2538 2538 (mole) 40.9
40.9 40.9 40.9 Weight average 2200 2120 1940 1810 molecular weight
______________________________________ *Weight % of terephthalic
acid residue in the polymer
To 100 parts by weight of the unsaturated polyester were added 3
parts by weight of an organic peroxide (Nippon Oil and Fats Co.,
Ltd., "PERBUTYL-O") and 50 ppm in concentration of cobalt acetate
as a crosslinking catalyst to give a polymerizable composition. The
polymerizable composition was applied in an amount of 50 g/m.sup.2
to a 50 .mu.m-thickness polyethylene terephthalate sheet, and the
coated sheet was passed through an oven at 150.degree. C. to heat
for 30 seconds for hardening, and thereby a coated sheet was
obtained.
Water immersion test
The coated sheet was cut into a size of 5 cm.times.10 cm to provide
a test sample. The test sample was immersed in a pure water for 5
seconds and pulled up from the water. The immersed test sample was
allowed to stand on a filter paper as the coated surface of the
unsaturated polyester being upside, and change of the test sample
was observed over 10 minutes to give the following results.
Example 8
The coated sheet was curled strongly, but wrinkles were slight and
the coated layer of the unsaturated polyester did not peel.
Example 9
The coated sheet was curled, but the coated surface of the
unsaturated polyester did not change and neither wrinkle nor
peeling was observed.
Example 10
The coated sheet was curled slightly but no remarkable change was
observed.
Comparative Example 2
The coated sheet scarcely changed.
Washing finish test
The coated sheet was slitted into a width of 5 cm to give lengthy
sheets. The lengthy sheets were applied, as the coated surface
being upside, to the bottom of a wood form (1 m.times.1
m.times.(depth) 10 cm) at intervals of 10 cm, the mortar used in
Example 2 was deposited at a height of 3 cm, and thereto
reinforcing steels (diameter 1 cm.times.80 cm) were arranged at
intervals of 20 cm and the mortar was furher deposited at the total
height of 6 cm. The resultant was allowed to stand at ambient
temperature for 168 hours, and the hardened molded plate was
removed from the form, the lengthy sheets were eliminated and
washing finish was conducted with a scrub brush while washing with
water. The results are as follows.
Example 8
A concave with a depth of about 2 mm was formed in the part in
contact with the sample sheet, and hence excellent washing finish
quality was observed.
Example 9
A concave with a depth of about 2 mm was formed in the part in
contact with the sample sheet, and hence excellent washing finish
quality was observed.
Example 10
A concave with a depth of about 1 mm was formed in the part in
contact with the sample sheet, and fair washing finish quality was
observed, but the depth of the concave was shallow in comparison
with Examples 8 and 9.
Comparative Example 2
Change of hue was observed in the part in contact with the sample
sheet, but there was no change in the surface roughness in
comparison with the non-contacted part with respect to the sample
sheet.
Example 11
A polymerizable composition was prepared by adding and mixing 10
parts by weight of styrene, 3 parts by weight of an organic
peroxide (Nippon Oil and Fats Co., Ltd., "PERBUTYL-O") and 50 ppm
in concentration of cobalt acetate as a crosslinking catalyst to
100 parts by weight of the unsaturated polyester obtained in
Example 8 (terephthalic acid content 5% by weight). A coated sheet
holding a cured product of the unsaturated polyester was
manufactured in the same manner as Example 8 except for employing
the above polymerizable composition, and the resultant sheet was
subjected to the water immersing test and the washing finish test
in the same manner as Example 8.
As a result, the sample sheet showed no noticeable curl and the
unsaturated polyester-coating surface exhibited no change in the
water immersing test. In the washing finish test, a washing finish
surface of about 2 mm depth was formed in the contact part with the
lengthy sheet.
Comparative Example 3
One side of a 50 .mu.m-thickness poly(ethylene terephthalate) sheet
was subjected to corona discharge treatment, and to the corona
discharge-treated side of the sheet was coated with an acrylic
tacky adhesive on a solid matter basis of 39 g/m.sup.2 in a gravure
role method, and the coated sheet was dried to give a tacky
adhesive sheet formed with a tacky adhesive layer.
Comparative Example 4
A tacky adhesive sheet was obtained in the same manner as
Comparative Example 3, except for applying the acrylic tacky
adhesive in an amount of 247 g/m.sup.2 on a solid matter basis.
Example 12
The procedure of Comparative Example 3 was repeated to give a tacky
adhesive sheet except for coating the sheet with a tacky adhesive
composition comprising 72% by weight (solid matter) of an acrylic
tacky adhesive and 28% by weight of a concrete retardative
composition in a proportion of 217 g/m.sup.2 on a solid matter
basis.
The concrete retardative composition is a mixed composition as
produced by adding 0.1 part by weight of cobalt naphthenate and 1
part by weight of t-butyl peroxybenzoate to a mixture comprising 50
parts by weight of an unsaturated polyester resin with a weight
average molecular weight of 3,000, 35 parts by weight of
hydroxyethyl methacrylate and 10 parts by weight of calcium
carbonate, which unsaturated polyester resin had been obtained by
reacting polyethylene glycol (molecular weight 300)/propylene
glycol/ethylene glycol/maleic anhydride=1/1/1/3 (by mole).
Example 13
A tacky adhesive sheet was obtained in the same manner as
Comparative Example 3 except for using the tacky adhesive
composition prepared in Example 12 in an amount of 246 g/m.sup.2 on
solid matter basis.
Example 14
By using the tacky adhesive composition prepared in Example 12 in a
proportion of, on solid mater basis, 100 g/m.sup.2, a tacky
adhesive sheet was provided in the same manner as Comparative
Example 3.
Example 15
The procedure of Comparative Example 3 was repeated to give a tacky
adhesive sheet, except for applying a tacky adhesive composition
comprising 52% by weight of an acrylic tacky adhesive (on solid
matter basis) and 48% by weight of the concrete retardative
composition of Example 13 in an amount of 50 g/m.sup.2 on solid
matter basis.
Example 16
A tacky adhesive sheet was provided in the similar manner as
Comparative Example 3, except for applying the tacky adhesive
composition prepared in Example 15 in an amount of 110 g/m.sup.2 on
solid matter basis.
Example 17
The procedure of Comparative Example 3 was repeated to give a tacky
adhesive sheet, except for using 200 g/m.sup.2 (solid matter basis)
of the tacky adhesive composition prepared in Example 15.
To the surfaces of the tacky adhesive layers of the tacky adhesive
sheets (50 cm.times.50 cm) each obtained in Comparative Examples 3
and 4 and Examples 12 to 17 were allowed to touch the surfaces of
tiles (about 15 cm.times.15 cm), and the tiles were adhered as
arranged 3 tiles in longitudinal direction and transverse direction
respectively (total 9 tiles/sheet) in the plane direction to
prepare unit tiles.
Each unit tile was disposed on the bottom of a form for concrete
placing (50 cm.times.50 cm.times.50 cm), a concrete was placed into
the form and was cured, the hardened concrete was removed from the
form, and the tacky adhesive sheet was eliminated, and a precast
concrete slab was obtained by washing-finish of the exposed
surfaces of the tiles with water.
To the precast concrete slabs each obtained in Comparative Examples
3 and 4, cement which had reached the surfaces of the tiles was
hardened and hence firmly adhered to the surface. Therefore,
mechanical surface finishing step was required to remove the
hardened cement which had not been eliminated by washing with
water. To the contrary, in the precast concrete slabs each prepared
by using the tacky adhesive sheets each obtained in Example 12 to
17, the cement reached the surfaces of the tiles was not completely
hardened after completion of curing, and the cement adhered to the
surfaces of the tiles could be removed only by means of washing
with water, and hence surface finish could easily be conducted with
inhibiting damage of the tiles. Incidentally, the adhesive
properties between the tacky adhesive layers and the tiles in the
unit tiles (that is, holding qualities of the tacky adhesive layers
with respect to the tiles) each obtained with the use of the tacky
adhesive sheets obtained in Comparative Examples 3 and 4, and
Examples 12 to 17 were fair.
* * * * *